1. Field of the Invention
This invention relates to a gauge assembly for monitoring the level of a liquid product in a storage tank or similar container, and to a convenient, user-friendly and reliable adjustable alarm for such a gauge assembly.
2. Description of the Prior Art
A great variety of devices have been used to monitor liquid product level in storage tanks and similar vessels. However, monitoring product level in storage tanks which contain petroleum products or other volatile liquids presents special requirements that have not been fully satisfied by the technology in common use today.
One device that has been used to monitor product level in such facilities is disclosed in U.S. Pat. No. 5,144,836 to Webb, the disclosure of which is hereby incorporated into this document. The Webb gauge utilizes a clock-type face that represents liquid product level in feet and inches, rather than in hours and minutes. The gauge further includes a float member that is intended during operation to be suspended near the surface of the product contained within the storage tank. A filament, kept taut by spring biasing, is attached to the float to sense the level of the float.
While a product level gauge such as that disclosed in the Webb patent can accurately indicate the level of product within the tank, it does not provide active protection against an overfill condition while the tank is being filled. Often, an operator is too busy to watch the gauge during filling of the tank.
It is clear that a long and unfilled need has existed in the prior art for an improved gauge assembly for monitoring the level of a liquid product that is capable of warning an operator of a potential overfill situation before it occurs.